Add function to print a number with grouped digits

Move bootstage's numbering printing code into a generic place so that it can
be used by tracing also.

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/vsprintf.c

@@ -870,3 +870,19 @@ char *simple_itoa(ulong i)
 	} while (i > 0);
 	return p + 1;
 }
+
+/* We don't seem to have %'d in U-Boot */
+void print_grouped_ull(unsigned long long int_val, int digits)
+{
+	char str[21], *s;
+	int grab = 3;
+
+	digits = (digits + 2) / 3;
+	sprintf(str, "%*llu", digits * 3, int_val);
+	for (s = str; *s; s += grab) {
+		if (s != str)
+			putc(s[-1] != ' ' ? ',' : ' ');
+		printf("%.*s", grab, s);
+		grab = 3;
+	}
+}